Major efforts included: (1) Analysis of joint risk of lung cancer from exposure to radon, arsenic and tobacco products; (2) data acquisition from large scale case-control and cohort studies in Gejiu City, China to further quantitate these relationships; (3) analysis-of data on risk of thyroid; cancer following exposure to radiation of the head and neck; (4) evaluation of case-control data on dietary risk factors for esophageal cancer; (5) evaluation of fecal mutagens; (6) studies of the effects of treatment for childhood cancer on subsequent rates of menopause and on patterns of marriage and divorce; (7) application of the method of backcalculation for projecting AIDS incidence and for estimating previous trends in infection for various subgroups of the population; (8) assisting members of the Viral Epidemiology Section on the design and analysis of studies of natural history, transmission rates, and biological markers in cohorts of hemophiliacs and infants exposed to HIV; (9) evaluating DNA fingerprints as an aid to quality control in tissue culture laboratories; (10) monitoring clinical trials of nutritional supplements to prevent cancer, of interventions to reduce smoking, and of therapies to prevent AIDS among infected groups; (11) providing consultation on the use of newly developed computing packages for epidemiologic analysis, and providing consultation on statistical methods to analyze error-prone exposures.